<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <iframe src="http://localhost:8000" frameborder="0" id="iframe"></iframe>
        <script>
            iframe.contentWindow.postMessage("hi", "*");
        </script>
    </body>
</html>
